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On the Precursor Environments to Mountain Lee Wave Clouds in Central Iberia under CMIP6 Projections
Mountain lee waves present significant hazards to aviation, often inducing turbulence and
aircraft icing. The current study focuses on understanding the potential impact of global climate
change on the precursor environments to mountain lee wave cloud episodes over central Iberia. We
examine the suitability of several Global Climate Models (GCMs) from CMIP6 in predicting these
environments using the ERA5 reanalysis as a benchmark for performance. The dataset is divided
into two periods: historical data (2001–2014) and projections for the SSP5–8.5 future climate scenario
(2015–2100). The variations and trends in precursor environments between historical data and future
climate scenarios are exposed, with a particular focus on the expansion of the Azores High towards
the Iberian Peninsula, resulting in increased zonal winds throughout the Iberian Peninsula in the
future. However, the increase in zonal wind is insufficient to modify the wind pattern, so future
mountain lee wave cloud events will not vary significantly. The relative humidity trends reveal no
significant changes. Moreover, the risk of icing precursor environments connected with mountain lee
wave clouds is expected to decrease in the future, due to rising temperatures. Our results highlight
that the EC-EARTH3 GCM reveals the closest alignment with ERA5 data, and statistically significant
differences between the historical and future climate scenario periods are presented, making ECEARTH3 a robust candidate for conducting future studies on the precursor environments to mountain
lee wave cloud events.The work is funded by the Ministerio de Ciencia e Innovación of Spain, through the PID2019-105306RB-I00/AEI/10.13039/501100011033 project
Southward migration of the zero-degree isotherm latitude over the Southern Ocean and the Antarctic Peninsula: Cryospheric, biotic and societal implications
The seasonal movement of the zero-degree isotherm across the Southern Ocean and Antarctic Peninsula drives major changes in the physical and biological processes around maritime Antarctica. These include spatial and temporal shifts in precipitation phase, snow accumulation and melt, thawing and freezing of the active layer of the permafrost, glacier mass balance variations, sea ice mass balance and changes in physiological processes of biodiversity. Here, we characterize the historical seasonal southward movement of the monthly near-surface zero-degree isotherm latitude (ZIL), and quantify the velocity of migration in the context of climate change using climate reanalyses and projections. From 1957 to 2020, the ZIL exhibited a significant southward shift of 16.8 km decade−1 around Antarctica and of 23.8 km decade−1 in the Antarctic Peninsula, substantially faster than the global mean velocity of temperature change of 4.2 km decade−1, with only a small fraction being attributed to the Southern Annular Mode (SAM). CMIP6 models reproduce the trends observed from 1957 to 2014 and predict a further southward migration around Antarctica of 24 ± 12 km decade−1 and 50 ± 19 km decade−1 under the SSP2-4.5 and SSP5-8.5 scenarios, respectively
Balance hídrico nacional. Número 1/2024
Balance hídrico correspondiente al 10 de enero de 2024